Enforced cam guidance for tool carriers

ABSTRACT

A positive cam drive arrangement for automatic processing machines wherein a tool carrier is mounted on a processing plate and a cam disc rotatably mounted on the plate carries a lead cam and a return cam. A connecting rod is pivotally attached adjacent one end thereof to the tool carrier. A followup arrangement is provided in which a lead cam follower rides against the lead cam and the return cam follower rides against the return cam, with one of the cam followers being biased into engagement with the associated one of the cams. A control lever extending substantially perpendicular to the connecting rod is pivotally attached to the connecting rod in order to minimize shearing forces.

United States Patent Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby Attorney-Bums, Doane, Swecker & Mathis ABSTRACT: A positive cam drive arrangement for automatic processing machines wherein a tool carrier is mounted on a processing plate and a cam disc rotatably mounted on the plate carries a lead cam and a return cam. A connecting rod is pivotally attached adjacent one end thereof to the tool carrier. A followup arrangement is provided in which a lead cam follower rides against the lead cam and the return cam follower rides against the return cam, with one of the cam followers being biased into engagement with the associated one of the cams. A control lever extending substantially perpendicular to the connecting rod is pivotally attached to the connecting rod in order to minimize shearing forces.

ATENTED JUN?? 19.:

SHEET E OF 2 ENFORCED CAM GUIDANCE FOR TOOL CARRIERS This invention relates to positive cam guidance for tool carriers on automatic processing machines, especially machines for stamped plate sectors, with a processing plate at the outside periphery of which a number of processing devices, such as bending rams or similar things, have been arranged radially shiftably toward the workpiece stretched in the middle. The cam guidance comprises a connecting rod connected to the tool carrier at one end, whose other end carries a followup arrangement controlled by a cam disc mounted on the processing plate against a lead and a return cam.

[t has been known to operate such tool carriers locking positively in the feed direction through a cam disc via a connecting rod having a cam follower moved by the lead cam directed toward the outside. The return in that case is accomplished by a spring. The follower runs off at that side of the curve ring facing the carrier. Through this arrangement the lead cam must run at a relatively small radial distance from the rotational axis of the cam disc, in order to avoid an unnecessary waste of space. As a result of that, changes in the radial height of the curve move along a smaller peripheral length and become very steep, which, for one thing, leads to very strong shearing forces on the connecting rod and thus to a tilting of the carrier, while, on the other hand, the load of the total of constructional parts becomes greater.

it is an object of the present invention to provide a cam guidance wherein essentially smaller shearing forces and essentially smaller loads of the constructional parts occur. According to the invention this is achieved through the fact that the rod runs almost diametrically across the cam disc with the followup arrangement supported against the sector facing the tool carrier on the guide cam as a lead cam directed toward the inside and on the guide cam as a return cam directed toward the outside.

In the case of a rapid sequence of strokes of the carrier, a great acceleration is required so that the return springs must be very strong. In order to prevent this, it has been known to put back the carrier in a positively locking manner through a return cam in parallel to the lead cam. In the use of followup rollers, in this during the changeover from the feed stroke to the return stroke, a change in the rotational direction of the roller occurs, as a result of which the latter receives very great accelerating forces. In order to avoid this, the followup arrangement according to the present invention includes two followup rollers, one of which rides against the feed cam and the other on the return cam.

Since, for the balancing of the necessarily present tolerances, the rollers lie with a certain play in the gap between the two guide cams, an impact against the rollers will take place during the change in the stroke whenever the roller which previously had ridden against its cam with play is made to fit against said cam.

According to the invention, this is avoided through the fact that the roller riding against the feed cam is connected in a positively locking manner and the roller running off on the return cam has been connected radially movably with the connecting rod via a spring element prestressed in the direction of support.

At the same time, the spring element can be a set of cup springs, whose progressive spring characteristic makes possible a slight compression for balancing out the construction tolerance of the guide cam with a small force, but which counteracts the return forces with a progressively strongly increasing spring force. The present compression of the spring element can be rendered adjustable by any suitable means such as an adjusting screw to adapt it to the various operating conditions.

At the same time, the roller riding against the return cam may lie on a leg of a scissorlike lever arrangement, whose other leg lies approximately at a right angle to the connecting rod. Alternatively it can lie approximately at right angles to the shearing arm on a control lever the axis of said shearing arm lying within the area of the rotational axis of the other roller, whereby the return cam is shifted at an angle against the feed cam by the angular distance of the two followup rollers from one another.

In order to avoid any shearing forces which may still occur on the connecting rod, which could lead to a tilting of the carrier and thus to increased wear and to imprecision in processing, according to a preferred embodiment of the invention a supporting control lever is provided, which, on the one hand, has been pivotally mounted to the end of the connecting rod carrying the followup arrangement and, on the other hand, to a point on the machine frame around axes at right angles to the plane of the guide cams, lying at right angles in relation to the connecting rod from this pivot point.

In order not to transfer the small transverse movement of the connecting rod to the carrier, which is conditional on the swinging movement of the supported control lever, the connecting rod must be connected with the carrier swivelably around an axis which is parallel to the leg axes of the supported control lever.

Whenever the roller riding against the return cam lies at a leg of a scissorlike lever arrangement, this can be the leg connected with the connecting rod in the case of an arrangement of a supported control lever.

In order to absorb a force transferred through the runningoff movement of the followup rollers at the lead cams of the cam disc to the latter, said force being perpendicular in relation to the lead cam, and thus to prevent a tilting movement of the cam disc the cam disc may be supported in the area of the lead cams by means of a thrust bearing.

Through the invention an extraordinarily precise guidance of the tools in the carrier is achieved even in the case of the most rapid stroke sequence, so that with the arrangement of the present invention, it is possible to maintain precisions of a few thousandths of a millimeter for the production of small parts with up to l ,000 tool carrier strokes per minute.

The invention will be explained in more detail in the following nonlimiting embodiments and drawings wherein:

FIG. 1 is a top view ofa positive cam guidance;

FlG. 2 is an enlarged sectional view along the line ll-ll in FIG. 1;

FIG. 3 shows a top view of a variation of the cam guidance of the ipvention on an enlarged scale; and

FIG. 4 shows a view similar to FIG. 3 of another variation of the invention.

There is shown in FIG. 1, a circular processing plate I, a tool carrier 3 guided radially movably in guides 2, which carrier 3 carries a pressing die 4. The carrier 3 is shown in the front dead center, in which it bends a sheetmetal strip 5 against a chucking matrix 6, 6. On the carrier 3, a connecting rod 8 is attached swivelably around an axis lying perpendicular to the path of movement of the carrier 3, by means of a hinge pin bearing 7. The connecting rod 8 runs diametrically across a cam disc 9 having a lead cam 10, which is directed radially inwardly, and a return cam 11, which is directed radially outwardly. At the rear end of connecting rod 8, a followup roller 12 is arranged on a bearing pin, which roller rides against the lead cam 10. Furthermore, a supported control lever 14 is pivotally mounted on the bearing pin of the roller 12 and around a swiveling pin 13, fixedly attached to the processing plate 1. The supported control lever 14 runs approximately at right angles to the connecting rod 8. At a distance from the pivot point of the supported control lever 14, on the connecting rod 8, a control lever 16 is pivotally mounted on a pin 15. The free end of the lever 16 carries a guide roller 17 riding against the return cam l l. The scissorlike control mechanism formed by the support control lever 14 and the swiveling control lever 16 is forced outwardly by a biased cup spring 18, which is located in a recess in the swiveling control lever 16. The spreading force exerted by the spring 18 can be adjusted by a knurled head screw 19 acting in the direction of compression of the spring 18'and screwed into a threaded bore coaxially aligned with the recess in the lever 16.

Through this arrangement the movement, carried out by the roller 12 upon starting up at the feeder lead cam 10, is transferred in a positively locking manner axially to the connecting rod 8 and from the latter via the pin 7 to the carrier 3. The radial movement carried out by the roller 17 during running off on the return cam lll is transferred by the control lever 16 via the spring E8 to the supported control lever M and from the latter to the connecting rod 8 and the carrier 3. This transfer of force takes place in a positively locking manner through interposition of the spring 18 and the corresponding prestress, so that tolerances in the space between the lead cam 10 and the return cam Ill are balanced out, and the impact absorbed during the turn of the movement of the stroke of the carrier 3 by the rollers 12 and 27 is cushioned. As a result of the fact that the carrier 3 is driven practically crosshead fashion, the shearing forces on the carrier 3 will be avoided and not only will the wear of the carrier guides 2 be decreased but also lateral movement of the die 4 will be avoided. Since the feed movement is transferred by the lead cam in a positively locking manner, an exceedingly precise control of the stroke results and precisions of stroke up to a few thousandths millimeters can be obtained. The shearing force transferred through the peripheral movement of the cams I10 and H via the rollers 12 and ll7 is absorbed through the supported control lever 14, which, on the one hand, does not impede the axial movement of the connecting rod 8, but on the other hand, permits only a very limited transverse movement in dependence on its radial movement at its free end, which through the pivotal attachment of the connecting rod 8 via the pin 7 to the carrier 3 will not transfer any harmful shearing forces or tilting forces to the carrier 3.

As shown in FIG. 2, the cam disc 9 is supported in the area of the lead and return cams 110 and H by a thrust bearing 20, so that through the movement of the tool or through a slight oblique position of the followup rollers 112 or 17, the forces transferred to the cams, and thus to the cam disc will be absorbed in the direction of the rotational axis of the lead cam 10, which forces could lead to a tilting movement of the cam disc 9. The cam disc 9 has been mounted on its rotational axis in customary hearings.

in the cam guidance according to the embodiment of the invention shown in FIG. 3, the cam disc 21 has a lead cam 22 along which the lead roller 24, mounted on a connecting rod 23, rolls off. A swiveling control lever 26 is mounted on a bearing pin 25 of the roller 24 at the free end of which lies the return roller 27, which runs off along the return cam 28. The control lever 26 is prestressed by way of a tension spring 30 attached to the connecting rod 23 via pin 29, on one end, and to the shaft of the return roller 27. Since, viewed from the pivotal point 31 of the cam disc 21, the roller 27 is displaced by the angle a in relation to the roller 24, the return cam 28 too must be arranged displaced by the same angle in relation to the lead cam 22. The control lever 26 does not have to pivot about the pivot 25 for the roller 24, but can also be mounted at some other point on the connecting rod 23, so that it will lie at approximately a right angle in relation to the connecting rod 23.

Also, the case of the embodiment given by way of example, according to lFlG. 3, the connecting rod 23, as shown in FIG. 1, can be pivotally mounted on the carrier, and a supported control 32, indicated by dash-dot lines, can be provided similarly to the supported control lever 14 according to FIG. ll, which absorbs the shearing forces occurring on the cams as a result of the running-off movement of the rollers.

In the case of the embodiment according to FIG. 4, given by way of example, the lead roller 42 has been mounted on the connecting rod on a pin 41, which roller 42 runs off on the lead cam 33. The return cam 44 is the outer wall of a guide rib 415 opposite the lead cam 43 at the outside, the rib being attached on the cam disc. The cam disc in the case of this embodiment given by way of example can be a spoked wheel for decreasing the moved masses.

The connecting rod 40 extends beyond the guide rib 45 and is provided with a slotted hole 416, in which the pin 47 of the return roller 48 is slidably mounted. A bearing stone 49 is guided shiftably in the longitudinal direction of the slotted hole 46. The pin 47 has been prestressed by means ofa set of cup springs 50 in the direction of the return cam 44. The outside of the set of cup springs 50 is supported by the front surface ofa winged screw 51 which has been screwed into a corresponding threaded bore of the threaded connecting rod 40, so that the compressing force of spring 50 will be adjustable. In order to prevent a tilting of roller 48, the connecting rod 40 at its outside end can be bent in the form of a hook over the height of the return cam 44. it can also have an additional slotted hole 46 at its hook sector which is bent back and can be provided with the bearing and pressure arrangement 49, 50 and 5]. In this arrangement too, a supported control lever 52, similar to the supported control lever M according to P16. l or 32 according to FIG. 3, indicated in dash-dot lines, can be provided.

Although the invention has been described in considerable detail with reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described above and as defined in the appended claims.

lclaim:

K. A positive cam drive arrangement for automatic processing machines comprising:

A. a processing plate;

B. a tool carrier mounted on the plate;

C. a cam disc rotatably mounted on the plate, the cam disc carrying a lead cam and a return cam;

D. a followup arrangement comprising:

1. a lead cam follower riding against the lead cam; 2. a spring-biased return cam follower riding against the return cam;

E. a connecting rod pivotally attached to the followup arrangement on one end and to the tool carrier on the other end, the connecting rod running approximately diametrically across the cam disc.

2. A positive cam drive arrangement for automatic processing machines comprising:

A. a processing plate;

B. a tool carrier adapted to receive a metalworking tool, the tool carrier being slidably mounted on the plate parallel to the upper surface thereof;

C. a cam disc rotatably mounted on the plate, the cam disc carrying a lead cam and a return cam;

D. a followup arrangement comprising:

1. a first control lever pivotally mounted on an axis perpendicular to the upper surface of the processing plate;

2. a second control lever pivotally mounted on the first control lever and being outwardly spring biased;

3. a lead cam follower rotatably mounted on the first control lever and riding against the lead cam;

4. a return cam follower rotatably mounted on the second control lever and riding against the return cam;

E. a connecting rod rotatably mounted at one end on the first control lever and on the other end on the tool carrier, the connecting rod running approximately diametrically across the cam disc, whereby rotation of the cam disc causes forward movement of the connecting rod across the cam disc by means of the lead cam and lead cam follower, and whereby further rotation of the cam disc causes positive return of the connecting rod by means of the return cam and the spring-biased second control lever.

3. A positive cam drive arrangement for automatic processing machines comprising:

a processing plate;

a tool carrier mounted on said processing plate;

a cam disc rotatably mounted on said processing plate, said cam disc carrying a lead cam and a return cam;

a connecting rod pivotally attached adjacent one end thereof to said tool carrier and extending substantially diametrically with respect to said cam disc; and

a followup assembly for transmitting movement to said connecting rod and including: a lead cam follower for riding against said lead cam, a return cam follower riding against said return cam, spring means for biasing at least one of said lead cam follower and said return cam follower against the associated one of said cams, and a control lever extending substantially perpendicular to said connecting rod, said control lever being pivotally attached adjacent one end thereof to said connecting rod, and being pivotally mounted adjacent the other end thereof, on said processing plate. 4. A positive cam drive arrangement according to claim 3 wherein:

said lead cam follower and said return cam follower each comprise a roller for riding against the associated one of said cams. 5. The positive cam drive arrangement according to claim 4 wherein:

said lead cam follower is rotatably mounted on said connecting rod; and said spring means biases said return cam follower into engagement with said return cam. 6. The positive cam drive arrangement according to claim 3 wherein:

said spring means comprises a set ofcup springs. 7. The positive cam drive arrangement according to claim 3 wherein said followup assembly further includes:

a second control lever carrying one of said lead cam follower and said return cam follower. 8. The positive cam drive arrangement according to claim 3 wherein:

said lead cam follower and said return cam follower are angularly displaced with respect to one another about said rotatable cam disc, and said lead cam and said return cam are similarly angularly displaced. 9. The positive cam drive arrangement according to claim 3 wherein:

said connecting rod is pivotally connected to said tool carrier and to said control lever about pivot axes substantially coplanar with one another and with the axis of rotation of said cam disc. 10. The positive cam drive arrangement according to claim 3 wherein:

said cam disc is supported in the area of said lead cam and said return cam by a thrust bearing. 

1. A positive cam drive arrangement for automatic processing machines comprising: A. a processing plate; B. a tool carrier mounted on the plate; C. a cam disc rotatably mounted on the plate, the cam disc carrying a lead cam and a return cam; D. a followup arrangement comprising:
 1. a lead cam follower riding against the lead cam;
 2. a spring-biased return cam follower riding against the return cam; E. a connecting rod pivotally attached to the followup arrangement on one end and to the tool carrier on the other end, the connecting rod running approximately diametrically across the cam disc.
 2. a second control lever pivotally mounted on the first control lever and being outwardly spring biased;
 2. A Positive cam drive arrangement for automatic processing machines comprising: A. a processing plate; B. a tool carrier adapted to receive a metalworking tool, the tool carrier being slidably mounted on the plate parallel to the upper surface thereof; C. a cam disc rotatably mounted on the plate, the cam disc carrying a lead cam and a return cam; D. a followup arrangement comprising:
 2. a spring-biased return cam follower riding against the return cam; E. a connecting rod pivotally attached to the followup arrangement on one end and to the tool carrier on the other end, the connecting rod running approximately diametrically across the cam disc.
 3. A positive cam drive arrangement for automatic processing machines comprising: a processing plate; a tool carrier mounted on said processing plate; a cam disc rotatably mounted on said processing plate, said cam disc carrying a lead cam and a return cam; a connecting rod pivotally attached adjacent one end thereof to said tool carrier and extending substantially diametrically with respect to said cam disc; and a followup assembly for transmitting movement to said connecting rod and including: a lead cam follower for riding against said lead cam, a return cam follower riding against said return cam, spring means for biasing at least one of said lead cam follower and said return cam follower against the associated one of said cams, and a control lever extending substantially perpendicular to said connecting rod, said control lever being pivotally attached adjacent one end thereof to said connecting rod, and being pivotally mounted adjacent the other end thereof, on said processing plate.
 3. a lead cam follower rotatably mounted on the first control lever and riding against the lead cam;
 4. a return cam follower rotatably mounted on the second control lever and riding against the return cam; E. a connecting rod rotatably mounted at one end on the first control lever and on the other end on the tool carrier, the connecting rod running approximately diametrically across the cam disc, whereby rotation of the cam disc causes forward movement of the connecting rod across the cam disc by means of the lead cam and lead cam follower, and whereby further rotation of the cam disc causes positive return of the connecting rod by means of the return cam and the spring-biased second control lever.
 4. A positive cam drive arrangement according to claim 3 wherein: said lead cam follower and said return cam follower each comprise a roller for riding against the associated one of said cams.
 5. The positive cam drive arrangement according to claim 4 wherein: said lead cam follower is rotatably mounted on said connecting rod; and said spring means biases said return cam follower into engagement with said return cam.
 6. The positive cam drive arrangement according to claim 3 wherein: said spring means comprises a set of cup springs.
 7. The positive cam drive arrangement according to claim 3 wherein said followup assembly further includes: a second control lever carrying one of said lead cam follower and said return cam follower.
 8. The positive cam drive arrangement according to claim 3 wherein: said lead cam follower and said return cam follower are angularly displaced with respect to one another about said rotatable cam disc, and said lead cam and said return cam are similarly angularly displaced.
 9. The positive cam drive arrangement according to claim 3 wherein: said connecting rod is pivotally connected to said tool carrier and to said control lever about pivot axes substantially coplanar with one another and with the axis of rotation of said cam disc.
 10. The positive cam drive arrangement according to claim 3 wherein: said cam disc is supported in the area of said lead cam and said return cam by a thrust bearing. 